how to update fork from original github code example

Example 1: update my fork repository at github

# Add the remote, call it "upstream":

git remote add upstream https://github.com/whoever/whatever.git

# Fetch all the branches of that remote into remote-tracking branches,
# such as upstream/master:

git fetch upstream

# Make sure that you're on your master branch:

git checkout master

# Rewrite your master branch so that any commits of yours that
# aren't already in upstream/master are replayed on top of that
# other branch:

git rebase upstream/master

Example 2: git update fork from original repo

$ git remote add upstream https://github.com/[Original Owner Username]/[Original Repository].git
$ git fetch upstream
$ git checkout master
$ git merge upstream/master
$ git push